adept technology GRouter3, Руководство пользователя

Страница: 12 / 69

Node Node
...
Node Node
...
Node Node
...
78 kbps LON 78 kbps LON 78 kbps LON
10/100 Mbps Ethernet
Network Management
ANSI 852 Interface
Internet
852 /709.1/IP/WiFi
Routers
Optional
WiFi to Ethernet Bridge
Ad Hoc 802.11b WiFi Channel
Fig.1.7: Example WiFi Ad Hoc Network
1
.
4.3. Roaming Connections
Finally, LON to IP gateways may be connected to specialized IP applications instead of to other
gateways. Connecting an IP application to a GR3 router provides these specialized applications
with roaming capabilities which would be difficult if these applications were required to be
directly connected to the 709.1 network (e.g., GadgetAnalyzer, LonMaker-3, etc.). An example of
how several GR3 routers can be interconnected to support an IP backbone for several LON
networks is show in Figure 2.5.
1.5. IP Addressing Modes
e GR3 router uses one of two forms of IP addressing: unicast and multicast. Multicast currently
only works when in manual mode.
e advantage of multicast is that for networks with multiple Gateways (especially in flood
mode), multicast may be more efficient. e disadvantage of multicast is that some internet
routers do not support it. Multicast mode can reduce the IP traffic relative to unicast when there
are a large number of 852 devices in the channel. Up to 255 devices per IP domain are supported
with multicast. Some older IP routers do not support multicast and therefore you will not be able
to route 852 packets across a unicast only router with multicast addressing. IP router support for
Multicast is not a concern when all the 852 devices share the same subnet. e following figures
illustrate the differences between multicast and unicast.
-12-